A cold front dropped southeast through Iowa during the day on the 9th and became stationary south of the state. During the night of the 9th into the early morning of the 10th, low pressure formed over Oklahoma. The low lifted northeast along the front during the day on the 10th. A large area of over running precipitation developed. The airmass became very unstable with a southerly jet of 35 to 40 kts lifting over the cooler air at the surface. Dew points at the 850 mb level were near +10 C. in the warm air. Considerable destabilization took place with elevated CAPE rising into the 3000 to 4000 J/kg range over the east half of Iowa. The freezing level was around 10,000 feet, while the available cape in the -10 to -30 C. layer was around 200 J/kg. Thunderstorms erupted over a large part of Iowa, with a line of stronger storms developing in the south central into parts of central Iowa. Thunderstorms produced nickel size hail in Jasper County, which covered the ground. Penny size hail covered the ground in Poweshiek County from another severe storm. To the northwest, snow, mixed with freezing rain and sleet at times, was the problem. The snow began accumulating around 0400 CST, with the heavier snow beginning around 0600 CST. Heavy snow fell over the northern two tiers of counties, with 6 to 10 inches common. The heaviest snow fell in a band from Palo Alto County, across Kossuth County, into Winnebago County with 8 to 10 inches common. In Cerro Gordo County, snowfall was lighter with 3 to 4 inches common. In addition to the snow, heavy sleet fell at the onset of of the storm. Reports of around an inch of sleet were received. The snowfall tapered off rapidly too the south of the heavy snow area with amounts south of U.S. Highway 20, south to Interstate 80, generally in the 1 to 3 inch range.